Late on Thursday, Apple released yet another build (12D74) of OS X 10.8.3 to developers for testing, though as with recent revisions there appears to be no significant code changes, and no new release notes or immediately-obvious differences. As before, Apple is asking testers to focus on graphics drivers, AirPlay, AirPort, Safari and Game Center. The company has already fixed a strange "file URL" bug that would cause all kinds of applications to spontaneously quit when the phrase "File:" followed by three slash marks was written, but has not yet released 10.8.3 to the public.

This twelfth release of a OS X system update sets a record for most revised builds. The previous build, numbered 12D68, was distributed on Valentine's Day. The repeated betas suggest that Apple is having some difficulty squashing -- or is still finding -- serious bugs that make the update unready for public release.

Users are hoping that the new version (when it finally arrives) will also fix some issues with Macbook battery life, which has experienced a small but measurable decline since the transition away from Lion (OS X 10.7.5 was the last version). Recent releases (including 10.8.1 and 10.8.2) have mitigated the issue back to within normal levels, but have not yet fully restored the levels seen in Lion. Recent builds of 10.8.3 have also referred to Apple making some improvements in Wi-Fi reception and reporting.